MC68HC711K4CFN4 Datasheet, PDF (71/80 Pages) Motorola, Inc – 8-Bit Microcontroller

11 Pulse Accumulator
M68HC11 K-series MCUs have an 8-bit counter that can be configured as a simple event counter or for
gated time accumulation. The counter can be read or written at any time.
The port A bit 7 I/O pin can be configured to act as a clock in event counting mode, or as a gate signal
to enable a free-running clock (E divided by 64) to the 8-bit counter in gated time accumulation mode.
CPU Clock
Cycle Time
1 Count —
Overflow —
Common XTAL Frequencies
8.0 MHz
12.0 MHz
(E)
2.0 MHz
3.0 MHz
(1/E)
500 ns
333 ns
Pulse Accumulator (Gated Mode)
(2⁶/E)
32.0 µs
21.33 µs
(2¹⁴/E)
8.192 ms
5.461 ms
16.0 MHz
4.0 MHz
250 ns
16.0 µs
4.096 ms
E ÷ 64 CLOCK
(FROM MAIN TIMER)
TMSK2 INT ENABLES
PIN
PA7/
PAI/
OC1
FROM
MAIN TIMER
OC1
FROM
DDRA7
INPUT BUFFER
AND
EDGE DETECTOR
OUTPUT
BUFFER
2:1
MUX
DATA BUS
PACTL CONTROL
PAOVI
PAOVF
PAII
PAIF
1
INTERRUPT
REQUESTS
2
TFLG2 INTERRUPT STATUS
PAI EDGE
PAEN
DISABLE
FLAG SETTING
CLOCK
OVERFLOW
PACNT 8-BIT COUNTER
ENABLE
PAEN
INTERNAL
DATA BUS
Figure 18 Pulse Accumulator System Block Diagram
M68HC11 K Series
MC68HC11KTS/D
MOTOROLA
71